1. Field of the Invention
The invention relates to an apparatus for transfer of a torque from an internal combustion engine to an auxiliary unit, particularly a compressor of an air conditioning system of a motor vehicle, having an auxiliary unit shaft and a pulley disposed on the auxiliary unit housing so as to rotate, wherein the pulley and the auxiliary unit shaft are connected with one another by way of an overload protection device, wherein the overload protection device is configured in such a manner that the connection between the pulley and the auxiliary unit shaft is interrupted if a predetermined torque is exceeded, wherein the overload protection device has a spring washer having multiple spring arms, which are connected, on the end side, with connection elements of a disk-shaped driver until the predetermined torque is reached.
2. The Prior Art
In motor vehicles equipped with an air conditioning system, the compressor of the air conditioning system is generally driven by the crankshaft of the internal combustion engine, by way of a belt drive. If the compressor of the air conditioning system fails, this has the result that the entire belt drive of the motor vehicle becomes jammed or is damaged.
In order to remedy this defect, apparatuses are known that have an overload protection device in the powertrain between the pulley of the compressor and the compressor shaft, which device guarantees that the drive connection between the pulley and the compressor shaft is interrupted if the compressor of the air conditioning system fails. The pulley can then rotate freely on the compressor housing, so that the entire belt drive of the motor vehicle is not jammed or damaged.
An apparatus having an overload protection device is known from EP 2 722 558A1. In this apparatus, the overload protection device has a spring washer that is connected with the pulley so as to rotate with it, as well as a driver element that is connected with the compressor shaft so as to rotate with it. The spring washer has spring arms that project radially outward beyond the actual washer and extend in the circumference direction, the ends of which arms is clamped in place between the driver element and clamping plates attached to the driver element. If the torque exceeds a predetermined amount, the ends of the spring arms slip out of this clamping connection, so that no further transfer of torque takes place between the pulley and the compressor shaft, and the pulley can rotate freely on the compressor housing.
The structure of this overload protection device is very complicated, specifically both with regard to its production and its installation, since the overload protection device consists of a plurality of individual parts, namely not only the spring element and the driver element, but also the additional clamping plates and rivet-type attachment elements for attaching the clamping plates on the driver element.
A similar apparatus having an overload protection device is known from US 2012/0285784 A1, which does not, however, have a driver as a separate component. Instead, multiple bores are symmetrically disposed on a common circumference, in a region of the pulley that borders on the belt profile, into which bores screw-shaped elements are inserted and secured by means of a counter-nut, wherein the screw-shaped elements have pocket-shaped mountings in the head region, on the outside, into which the end of a spring arm of a spring washer engages, in each instance. In this regard, the mountings and the ends of the spring arms are structured in such a manner that in the event of an overload, the ends of the spring arms can slip out of the mountings. The structure of this overload protection device is also very complicated and requires improvement.